A business has high variable costs when many of its costs change depending on the amount of business it does. Because a car wash requires more supplies, utilities and employees when it's doing a high volume of business, car wash owners can expect high variable costs. In fact, almost all of the costs associated with running a car wash are variable ones.

Employees and Labor

Your employees are a significant source of costs. Salaries, benefits and employee training can cost thousands of dollars each month. If your business is successful, you may need to hire more employees or promote part-time employees to full-time status. The costs of paying overtime -- one and a half times the employee's hourly rate -- and covering your share of payroll taxes can creep up steadily as you gain more business.

Cleaning and Other Supplies

You can't run a car wash without soap, wax, cloths, car fragrances and similar items. The amount you'll spend on these items is directly tied to how much business you're doing. A successful car wash will have to invest much more in cleaning supplies and may decide to operate a small convenience store stocked with cards, foods and similar items. This can cut into your profits, but buying in bulk may help reduce the amount you spend.

Variable Utilities

Car washes can quickly run up high utility bills. You'll have to pay the costs of electricity and water, and if you offer hot-water treatments, your costs can go even higher. The more cars you service, the more utilities you'll use. You might opt to pay for cable or Internet service as your client base increases, but because these utilities usually charge a flat fee, your costs won't vary after you sign up.

Professional Services

Successful businesses have to review and revise contracts and may even face lawsuits from customers or employees. The more business you do, the more likely it is that you'll run into a legal problem, and the cost of an attorney can become a variable business cost. Likewise, you may have to contract with advertising agencies, and the amount you spend can depend on how much business you're doing. The costs of most professional services will generally increase along with your customer base.

About the Author

Van Thompson is an attorney and writer. A former martial arts instructor, he holds bachelor's degrees in music and computer science from Westchester University, and a juris doctor from Georgia State University. He is the recipient of numerous writing awards, including a 2009 CALI Legal Writing Award.